Improved detection of echocardiographically occult left ventricular thrombi following ST-elevation myocardial infarction

Abstract

Abstract Background and Aims Patients with STEMI are at significant risk for developing left ventricular thrombi (LVT). However, this complication often (up to 65%) remains undetected by using transthoracic echocardiography (TTE), referred to as TTE-occult LVT. The aim of this study was to investigate predictors of TTE-occult LVT and to propose a clinical model for improved detection of TTE-occult LVT post ST-elevation myocardial infarction (STEMI). Methods In total, 870 STEMI patients underwent TTE and cardiac magnetic resonance (CMR), the reference method for LVT detection, 3 days after infarction. Clinical and echocardiographic predictors were analyzed. Primary endpoint was the presence of TTE-occult LVT identified by CMR-Imaging. Results From the overall cohort, 37 patients (4%) showed an LVT by CMR. Of these thrombi, 25 (68%) were not identified by TTE. TTE-occult thrombi did not significantly differ in volume (1.4 vs. 2.74cm3), diameter (19.0 vs. 23.3mm), number of fragments or shape compared with TTE-apparent LVT (all p>0.05). For predicting these TTE-occult LVT, apical wall motion score using the 16-segment model (AWMS16Seg) showed highest validity (AUC:0.91 [95%CI:0.89-0.93];p<0.001), with an association independent of ejection fraction and AWMS17Seg (OR:1.68 [95%CI:1.43-1.97];p<0.001), clinical (body mass index, peak troponin) and angiographic (culprit lesion, post-interventional TIMI flow) associates of TTE-occult LVT (all p<0.05). Dichotomization at AWMS16Seg≥8 (n=260, 30%) allowed for a detection of all TTE-occult LVT (sensitivity:100%), with a corresponding specificity of 77%. Conclusions After acute STEMI, AWMS16Segserved as simple and very robust predictor of TTE-occult LVT. An AWMS16Seg-based algorithm to identify patients for additional CMR-imaging offers great potential to optimize detection of TTE-occult LVT following STEMI.Key IllustrationProposed Algorithm